Electronic organ with rhythm attachment employing selective operation of conventional or rhythmic sounds

ABSTRACT

A rhythm attachment, or unit, for an electronic organ, in which a pulse generator is provided which generates pulses according to predetermined timed patterns. The pulses thus generated are selectively supplied to voicing circuits in the rhythm unit to produce rhythmic accompaniment sounds through the electroacoustic system of the organ. The pulses generated can also be taken off ahead of the voicing circuits referred to for actuating gates interposed between the tone generating system of the organ and the electro-acoustic system to provide for rhythmic sounding of the regular organ voices. The organ can be adjusted for conventional manual operation, or for production of the rhythmic sounds.

United States Patent [191 Robinson et al.

Filed:

ELECTRONIC ORGAN WITH RHYTHM ATTACHMENT EMPLOYING SELECTIVE OPERATION OF CONVENTIONAL OR RHYTHMIC SOUNDS Inventors: John W. Robinson, Jasper; Arthur W. Ross, Ferdinand, both of 111.

Assignee: Jasper Electronics Manufacturing Company, Jasper, Ind.

Nov. 29, 1972 Appl. No.: 310,394

Related US. Application Data Continuation of Ser. No. 121,727, March 8, 1971, abandoned.

References Cited UNITED STATES PATENTS Oct. 22, 1974 3,548,065 12/1970 Freeman 84/l.()3 3,567,838 3/1971 Tennes et al. 3,585,891 6/1971 Schwartz et al. 84/1.()3 3,624,263 11/1971 Uchiyama 3,697,664 10/ l 972 Hiyama 3,708,602 1/1973 Hiyama 84/1.03 3,711,618 l/l973 Freeman 214/103 Primary Examiner- Richard B. Wilkinson Assistant ExaminerStanley .l. Witkowski Attorney, Agent, or Firm-Melvin A. Crosby [57] ABSTRACT A rhythm attachment, or unit, for an electronic organ, in which a pulse generator is provided which generates pulses according to predetermined timed patterns. The pulses thus generated are selectively supplied to voicing circuits in the rhythm unit to produce rhythmic accompaniment sounds through the electroacoustic system of the organ. The pulses generated can also be talgen off ahead of the voicing circuits referred to for actuating gates interposed between the tone generating system of the organ and the electroacoustic system to provide for rhythmic sounding of the regular organ voices. The organ can be adjusted for conventional manual operation, or for production of the rhythmic sounds.

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W W INVENTOR JOHN w. aomysou BY ARTHUR w. R055 ELECTRONIC ORGAN WITH RHYTHM ATTACHMENT EMPLOYING SELECTIVE OPERATION OF CONVENTIONAL OR RHYTHMIC SOUNDS This isa continuation of application Ser. No. 121,727, filed Mar. 8, 1971, and now abandoned.

This invention relates to electronic organs and is particularly concerned with an arrangement for producing rhythm sounds in a novel and relatively simple manner during playing of the organ.

Electronic organs are well known and comprise, basically, tone generators and voicing circuits for modifying the shape of the waves produced by the tone generators and electrocoustic sound producing means which are supplied by the outputs from the voicing circuits and key operated control switches located ahead of the sound producing means. It is also known to provide rhythm devices for use with electronic organs either as separate, free running units, or as units which are under the control of the organist as, for example, by the pedal keys of the organ and which rhythm units will produce percussion sounds such as drum and marimba sounds and the like and according to any predetermined rhythm schedule. The rhythm schedule, for example, might be in waltz time, march time, or any of the other well known music rhythm patterns, including more complex patterns such as the tango and rumba patterns.

The use of a rhythm attachment in connection with an electronic organ is especially useful to more or less expert players, and players of lesser skill and beginners can encounter considerable difficulty in producing good results while playing an organ in accompaniment with a rhythm unit.

It is particularly difficult for novices to play an instrument in accompaniment with a free running rhythm unit because the speed of the rhythm unit is constant and the playing of the instrument must be at the same constant speed in order for the combined outputs of the organ and rhythm unit to sound right.

Even with rhythm units which are triggered by the actuation of a pedal of the pedal clavier so that the speed of the rhythm unit is continuously adjusted to playing speed, some considerable difficulty can be encountered by a novice because the rhythm unit so triggered by actuation of a pedal key will run through a complete measure at a certain speed, again presenting the player with a problem of synchronization.

Having the foregoing in mind, the present invention proposes an arrangement wherein rhythm sounds can be produced in an electronic organ merely by holding down the keys thereof. In particular, the present invention proposes a circuit arrangement such that a holding down of the keys of the accompaniment manual, for example, a chord, and the holding down of at least one key of the pedal clavier, will result in the production of rhythm sounds in accordance with the keys that are held down while the melody can be played on the solo manual of the organ.

The present invention is also concerned with the provision of an arrangement of the nature referred to in which the rhythm unit can produce customary rhythm sounds in a conventional manner independently of the actuation of the keys of the organ accompaniment manual and pedal clavier.

Still further, the present invention proposes an arrangement of the nature referred to in which the keys of the accompaniment manual and pedal clavier of the organ can be operated in a conventional manner without being under the influence of the pulses from the rhythm attachment.

BRIEF SUMMARY OF THE INVENTION According to the present invention, a rhythm unit is provided having a pulse generator and voice circuits adapted to be actuated by the pulses to produce rhythm sounds. Pulses taken off from the pulse generator of the rhythm unit ahead of the voice circuits thereof are employed for selectively actuating gate-like components interposed between the pedal clavier output of an electronic organ and the organ amplifier and speaker and also between the accompaniment manual output of the organ and the amplifier and speaker of the organ so that keys of the pedal clavier and accompaniment manual will sound only when the gate-like components are actuated by pulses from the rhythm attachment.

Any selected rhythms from the rhythm unit can be delivered to either one or both of the lower manual or pedal clavier of the organ and, in this manner, complex and pleasing rhythm patterns can be established to accompany the upper manual and even a novice player can produce good results.

The gate-like components can be selectively held open or placed under the control of pulses from the rhythm unit and, also, the rhythm unit from which the pulses for actuating the gate-like components are derived can also be made selectively effective or ineffective for producing rhythm sounds.

The exact nature of the present invention will become more apparent upon reference to the following detailed specification, taken in connection with the accompanying drawings, in which:

FIG.'1 is a schematic simplified block diagram showing an arrangement according to the present invention;

FIG. 2 is a schematic diagram showing more in detail a part of the selector switch network of the rhythm unit, the interconnections between the rhythm unit and the circuit of the organ according to the present inven- IIOI'I,

FIG. 3 is a schematic diagram showing in detail of a portion of the circuit of the present invention that is contained within the organ and showing the gate-like components controlling the outputs from the accompaniment manual and pedal clavier;

FIG. 4 is a graph showing the variation of the source to drain resistance of an F .E.T. transistor as the voltage at the source changes;

FIG. 5 shows a simple F.E.T. signal modification device with one type of voltage supply to the gate;

FIG. 6 shows an improved circuit arrangement having the same type of voltage supply to the gate as in FIG. 5;

FIG. 7 shows a circuit like that of FIG. 5 with a different type of voltage supply to the gate; and

FIG. 8 shows an improved circuit having the same type of voltage supply to the gate as in FIG. 7.

DETAILED DESCRIPTION Referring to the drawings somewhat more in detail, in FIG. l, 10 schematically illustrates an electronic organ having solo manual 12, an accompaniment manual 14 and a pedal clavier 16. The organ has therein tone generating means 11 and'voicing circuit means 13 according to usual practices so that the depressing of keys thereof will cause certain voices, selected by tab switches in circuit with the voicing circuit means, to sound through the amplifying and speaker system of the organ. In FIG. 1, the amplifier is generally indicated at 18 and a speaker is shown at 20, but it will be understood that more than one amplifier and more than one speaker could be provided if so desired.

FIG. 1 also schematically illustrates a rhythm unit 22 which may be of the conventional design and which has a plurality of selector buttons 24 for selecting certain rhythm patterns. The rhythm patterns supplied by the rhythm unit are in the form of pulses occurring at cer tain time intervals and by combiningthe pulses through a network, such as a diode network, substantially any known musical pattern can be provided. The rhythm unit comprises voicing circuits supplied by the aforementioned pulses and which develop percussion sounds that are passed through an amplifier in the unit and then to the organ speaker system or through a speaker system associated with the rhythm unit. In FIG. 1, the voicing circuits and amplifier of the rhythm unit are designated 25.

A switch 27 may be provided to mute the rhythm unit, and a switch 29 for turning the rhythmunit on and off. A knee operated switch-31 may parallel switch 29. The unit has an output jack 33 and a volume control element 35 can be provided for the rhythm unit.

According to the present invention connections are made to the rhythm unit ahead of the voicing circuits thereof for deriving certain pulses therefrom which are then supplied to the control terminals of gate-like components 36 and 34 by wires 30 and 32 each having a resistor R1 and capacitor C1, in circuit with the outputs from accompaniment manual 14 and pedal clavier 16 by wires 41 and 39. A further connection from the rhythm unit to the control terminal of gate component 36 includes an emitter follower E1 and a capacitor C2.

The output from the pedal clavier 16 is connected to component 34 by wire 39 while the output from lower manual 14 is connected to component 36 by wire 41. The output sides of components 34 and 36 may be interconnected and connected to the input side of the organ output amplifier by wire 42.

When components 34 and 36 are placed under the control of pulses from the pulse generator of the rhythm unit the depressing of keys of the accompaniment manual or one or more keys of the pedal clavier will not produce sounds unless pulses are supplied to the control terminals of the said components 34 and 36. The pulses for controlling the gates become available when the rhythm unit is turned on and is running.

At this time, namely, when the rhythm unit is running the rhythm unit may be producing outputs at jack 33 which sound through its own speaker, or through the organ speaker, or the output from the rhythm unit can be muted or by-passed to ground. The pulses developed in the rhythm unit, however, are produced all the time that the unit is running, namely, while either of switches 29 or 31 is closed, and it is selected ones of these pulses, supplied, via a suitable circuit, to the control terminals of components 34 and 36, that operate components'34 and 36.

When components 34 and 36 are not under the control of pulses from the rhythm unit, the components are in a conductive state and the outputs from the accompaniment manual and pedal clavier pass directly therethrough to wire 42 for conventional organ operation. At this time, of course, the rhythm unit 22 can either be running or shut off, as the organ player desires.

Each component 36 and 34 has a switch 39', 41 by means of which it can be made selectively effective, i.e., placed under the control of pulses from the rhythm unit 22, or ineffective, or a single switch can be provided to control the components as a unit.

FIG. 2 shows more in detail the rhythm unit of FIG. 1 and the manner of taking pulses therefrom.

In FIG. 2, the rhythm unit will be seen to comprise a timing generator 50 having a plurality of wires 52 leading therefrom and on which wires are developed pulses bearing timed relation to each other. The wires 52 lead into a matrix 54, a diode matrix, for example, in which the pulses are combined to provide for outputs .on wires 56 which have predetermined pulse patterns under the control of pushbuttons 24 to provide at output wires 60 a plurality of rhythm patterns pertaining to various types of music. A typical switch arrangement of the type referred to is shown in US. Pat. No. 3,548,065. The wires 60 are connected to the portion 25 of the rhythm unit which contains the voicing cir cuits and amplifier and which includes the aforementioned volume control element 35 and output jack 33, as well as the muting switch 27.

The connections to the input terminals of the components 34 and 36 previously referred to are made from wires 60 ahead of portion 26 via the diodes D1 to via and the aforementioned component El, and which is an emitter follower arrangement, for signal isolation and anti-loading and for pulse amplification.

As will be seen, the wire 30 leading to the control ter minal of component 34 pertaining to the pedal clavier, may be connected to three of the wires 60 via respective diodes D5, D7, and D8, while the wire 32 pertaining to component 36 may be connected to five of the wires 60 via respective diodes D1, D2, D3, D4 and D6, as well as to a further one of wires 60 via the emitter follower component E1.

The number of diode connections to wires 60 may be greater or lesser than what is shown.

It will be perceived that the rhythm unit, upon actuation of either of switches 29 or 31, will operate and, depending on the setting of pushbuttons 24, will supply rhythm patterns to one or more of wires 60 and which can actuate the voice circuits of the rhythm unit or can actuate the components 34 and 36 selectively as may be desired.

FIG. 3 shows more in detail the components 34 and 36 and each of which is, essentially, a monostable multivibrator triggered by pulses from the rhythm unit followed by a pulse invertor and a pulse shaper and, finally, by a gate in the form of a field effect transistor (FET). The two components 34 and 36 are substantially identical, except for certain parameters, and only one thereof will be described in detail. The only differ- 'ence between the two components is that the component 34, pertaining to the pedal clavier, is adjusted to ment manual are preferably more staccato than the rhythm sounds developed by the pedal clavier, which it is desired to sustain for a somewhat longer time.

Referring more particularly to F IG. 3, and with particular reference to component 34, which is the lower part of FIG. 3, the line 39 representing the audio output from the pedal clavier, is connected through a capacitor C3 to ground and through a capacitor C4 to the base of a transistor Q12 which forms an input preamplifier. The base of transistor Q12 is also connected to ground through a resistor R2 and is connected through a resistor R3 to a bias wire 70 leading through a resistor R4 to a wire 72 which is at about 1 3 volts. A capacitor C13 connects wire 70 to ground. Wire 70 is connected through resistor R5 .with the collector of transistor Q12 while the emitter of transistor Q12 is connected to ground via a resistor R6. The collector of transistor Q12 is connected through a further capacitor C5 and a resistor R7 to the juncture of a pair of serially arranged resistors R8 and R9 with the opposite end of resistor R9 being grounded and the opposite end of resistor R8 being connected to the source terminal of an FET transistor Q11 which forms a gate.

The drain terminal of transistor Q11 is connected to ground via a resistor R10 and through a capacitor C6 to the base of a transistor Q13 which forms an output preamplifier. The base of transistor Q13 is also connected through a resistor R11 to ground and through a capacitor C7 to the emitter of transistor Q13 and through further serially arranged resistors R12 and R13 to the collector of transistor Q13. The juncture of resistors R12 and R13 is connected to the source of bias voltage represented by wire 70. The collector of transistor Q13 is connected through a capacitor C8 to ground and through a capacitor C9 and resistor R14 to the output terminal of component 34 which, as previously described, is connected to wire 42 leading to the input side of the organ amplifier. The emitter of transistor Q13 is connected to ground via a resistor-capacitor network.

The gate terminalof FET transistor Q11 is connected via a resistor R15 with a slider 71 engaging a resistor R15 which has one end grounded and the other end connected through a resistor R16 with the negative side of a diode D9, the positive side of which is connected through the serially arranged resistors R17 and R18 to wire 72. A capacitor C5 and a resistor R8 are connected in series between the source terminal of transistor Q11 and the end of resistor R15 opposite the gate terminal end thereof.

A further resistor R19 is connected between the juncture of resistors R17 and R18 and the negative side of diode D9 and also through a capacitor C10 to ground. Resistors R15, R16, R17 and R19, together with diode D9 and capacitor C10 form a pulse shaping network which determines the rise time and decay time of the pulse supplied to the gate terminal of transistor Q11. 2

The juncture of resistors R17 and R18 is also connected to the collector of a transistor Q10 forming a pulse inventor, and the emitter of which is grounded while the base thereof is connected through a resistor R20 to the collector of a transistor Q8. The collector of transistor Q8 is also connected through resistor R22 with the base of a transistor Q9, the emitter of which is grounded and the collector of which is connected through resistor R24 to wire 72 and also through capacitor C11 to the base of transistor Q8.

The collector of transistor Q8 is also connected through a resistor R26 to a wire 72 and the emitter thereof is grounded. The base of transistor 08 is connected via the aforementioned capacitor C1 and resistor R1 with wire 30 and also through a capacitor C12 and resistor R28 to ground. The base of transistor 08 is, furthermore, connected through a resistor R30 with one side of on-off switches 29 and 31, the other sides of which are connected to wire 72 which, as mentioned, is at about -13 volts.

Wire 72 is connected through a resistor R32 with a -18 volt source while a zener diode D10 maintains a constant voltage level on wire 72 and is connected in parallel relation with a filter condenser C14.

The circuit generally described above is substantially the same as that illustrated in the issued United States Patent No. 3,497,605, and provides for the transfer of signals from wire 39 to wore 42 via transistors O12, Q11 and Q13 whenever transistor Q11 is conductive. Transistor Q11 is continuously conductive when component 34 is not being used as a rhythmatic device. However when switch 29 or 31 is adjusted to place component 34 in use as a rhythmic device, transistor Q11 is biased to a non-conductive state. Thereafter, upon the supply of a pulse to wire 30 from the rhythm unit, a control pulse is generated and supplied to the base of FET transistor Q11 which allows Q11 to conduct for a predetermined time.

It will be apparent that transistors Q8 and Q9 form a monostable multivibrator with a period determined, in part, by the size of capacitor C11. The period of the multivibrator will, in turn, control the duration of the control pulse supplied to the base of pulse inverting transistor Q10 which will control the duration of the control pulse supplied, via the pulse shaping network, to the gate terminal of transistor Q11.

The elements of the component 36 pertaining to the accompaniment manual have been given the same numerals as the elements of component 34 with the addition of a subscript a. In component 36, capacitor C1 1a is only about one-third the size of capacitor C11 of component 34 to provide for a shorter period for the monostable multivibrator consisting of transistors Q8a and Q9a, and, therefore, a shorter duration of the con trol pulse supplied to the gate terminal of FET transistor Qlla. The rhythm sounds from the accompaniment manual are, thus, more staccato than those from the pedal clavier.

In operation, and referring to component 34 in FIG. 3, if switches 29 and 31 are open, transistor Q8 will be nonconductive and transistor Q10 will be turned on, thus holding the gate terminal of transistor Q11 at about zero potential, and at which potential level the impedance of transistor Q11 is quite low, so that signals keyed by the pedal clavier will readily pass from the input preamplifier transistor Q12 to the output preamplifier of transistor Q13.

If, however, either of switches 29 or 31 is closed, transistor O8 is at saturation and transistor Q10 is turned off thereby permitting the gate terminal of transistor Q11 to go negative, whereupon transistor Q11 will present a high impedance and prevent the passage of signals therethrough. Positive pulses supplied to wire 30, however, will trigger the monostable multivibrator consisting of transistors Q8 and Q9 which will result in the supply of actuating pulses to the gate terminal of transistor 011.

The operation of component 36 is the same as that described for component 34 except the smaller size of capacitor Clla provides for a substantially shorter on time for the monostable multivibrator and, therefore, a shorter duration of the actuating or enabling pulses supplied to. the gate terminal of transistor Q1 1a.

The aforementioned component E1 will be seen to consist of a transistor 07 which, when actuated by signals supplied to the base thereof, will develop signals onthe emitter follower resistor R40 which will be supplied via capacitor C2 to the input terminal of component 34.

In view of the foregoing description, reference may now again be had to FIG. 1, wherein each of the components 34 and 36 will be seen to comprise a monostable multivibrator followed by a pulse invertor followed by a pulse shaper and then finally followed by a gate, and which gate is open when the monostable multivibrator is disabled. The gates are normally closed when the respective monostable multivibrator are enabled, except when trigger pulses are supplied to the monostable multivibrator.

It has been mentioned that the component 34 and 36 can be individually enabled or disabled by providing independent switches therefor and that the rhythm unit can be selectively enabled or disabled in respect of sound production whether or not the system of the present invention is in operation.

With reference to the FET transistors employed, the present invention comprises circuity which modifies the response of FET transistors to control the signal modification effective thereby.

FIG. 4 is a graph showing how the resistance from the drain terminal to the source terminal in an F ET transistor varies with the voltage between the gate and source terminals. It will be seen in FIG. 4 that the resistance is not linear but varies with the voltage of the signal at the source. As the voltage at the source increases in the positive direction, the resistance between the drain and source terminals will decrease whereas, as the voltage at the source terminal increases in the negative direction, the said resistance will increase. Thus, in cases where the voltage signal at the source terminal varies, a nonlinearity is introduced into the output signal and which will become more pronounced as the voltage of the signal at the source terminal increases in amplitude.

It has been discovered, however, that by modifying the conventional connections in an FET transistor, the effect of the nonlinearity referred to can be eliminated substantially completely.

Toexplain the foregoing, FIG. 5 shows a conventional FET transistor hook-up with the signal supplied to the source terminal marked Vs and the signal supplied to the gate terminal marked Vg while the signal from the drain terminal is marked V0. The resistance between the source and drain terminals is marked Rds.

FIG. 5 also shows voltage configurations with the signalat the source terminal indicated by the line at Vs and that at the gate terminal marked at Vg. The frequency of the voltage supplied at Vg is substantially less than that supplied to the source terminal. The important voltage for determining the output from the transistor is the voltage standing between the source and gate terminals and this is indicated at Vgs in FIG. 5 and will be seen to vary in conformity with both the voltage signal at the source terminal and the voltage signal at the gate terminal. This variation in the voltage between the gate and source terminals, is indicated by the voltage line Vgs, leads to nonlinearity in the output of the transistor.

FIG. 6 shows a modified circuit according to the present invention in which this nonlinearity is compensated by introduction of a resistor Rjb connected between the source and gate terminals. The provision of the resistor provides for a transfer or feedback of voltage from the source terminal to the gate terminal so that the voltage at the gate terminal is modulated by the voltage at the source terminal, whereby the important control voltage, namely, the voltage standing between the gate and source terminals becomes more constant and results in a linear output varying in conformity with the voltage signal at the gate terminal.

FIG. 7 shows an arrangement similar to that illustrated in FIG. 5, and the same reference numerals are employed, but the signal supplied to the gate terminal is of a different type and changes linearly from one voltage to another over a certain interval.

FIG. 7, furthermore. shows the output signal marked Vo which will be seen to be nonlinear due to the variations in the voltage standing between the gate and source terminals.

FIG. 8 shows how the transistor of FIG. 7 can be modifiedby the addition of a feedback circuit which takes the form of a resistor Rfb and a capacitor C 'fb connected in series between the gate and source terminals of the transistor. In the case of FIG. 8, the source of signals for the gate terminal is marked V'g and is connected through a resistor Rg with the gate terminal of the transistor.

FIG. 8 also shows the voltages obtaining at the various terminals in the circuit and, in particular, the important voltage marked Vg, which is that that appears at the gate terminal of the transistor, and will be seen to vary in conformity with both the voltage signal Vs at the source terminal and the voltage signal Vg supplied to resistor Rg.

The voltage between the source terminal and gate terminal, marked Vgs, will be seen to vary in conformity with the source of control voltage signals V'g so that the output signal at V0 will be seen to vary in a linear manner rather than in a nonlinear manner as shown in FIG. 7.

By the inclusion of the feedback branch in the FET transistor circuitry, the entire transistor circuit becomes useful as an analog switch for switching analog voltages without distortion thereof.

Modifications may be made within the scope of the appended claims.

What is claimed is:

I. The method of operating an electronic organ having solo and accompaniment manuals and a pedal clavier and an electroacoustic system supplied thereby which comprises; connecting a respective gate having a voltage sensitive control terminal between the output side of each of said accompaniment manual and pedal clavier and said electro-acoustic system, supplying steady state gate opening voltage to the control terminal of each said gate for conventional organ playing and during which organ sounds are produced continuously while corresponding keys of the accompaniment manual and pedal clavier are depressed, and selectively interrupting said steady state opening voltage supply and instead supplying respective trains of pulses of gate opening voltage to the respective control terminals of said gates according to selected predetermined repeated and respective rhythm patterns for playing of the organ with depressing of keys of the accompaniment manual and pedal clavier producing sounds which are intermittent in conformity with the patterns of pulses supplied to the control terminals of the respective gates.

2. The method according to claim 1 in which the individual pulses of gate opening voltage supplied to the control terminals of the respective gates are of respectively different duration.

3. The method according to claim 1 in which the individual pulses of gate opening voltage supplied to the control terminal of the gate for the accompaniment manual are of shorter duration than those supplied to the control terminal of the gate for the pedal clavier.

4. In combination; key controlled signal source means operable to develop electric tone signals, tone signal receiver means including electroacoustic means operable to convert the tone signals to sound, gate means having input terminal means connected to the output side of said signal source means and output terminal means connected to the input side of said signal receiver means, said gate means having control terminal means and varying in impedance in conformity with variations in voltage at said control terminal means, means forming a source of voltage pulses which occur in selectable predetermined repetitive rhythmic patterns, monostable multivibrator means having output terminal means connected to the control terminal means of said gate means, said multivibrator means having trigger terminal means connected to said source of voltage pulses, a source of bias voltage which will hold said multivibrator means in one state when supplied to the said trigger terminal means thereof, said one state of said multivibrator means being that state in which the voltage supplied to said control terminal means makes the impedance of the said gate means low, and switch means connected between said source of bias voltage and said trigger terminal means and in one position connecting said source of bias voltage to said trigger terminal means to hold said multivibrator means in said one state and in another position disconnecting said source of bias voltage from said trigger terminal means thereby releasing said multivibrator means to the control of pulses supplied thereto from said source of voltage pulses for rhythmic changes of state of said multivibrator means, said multivibrator means when under the control of said voltage pulses from said source of voltage pulses causing the impedance of said gate means to alternate between high and low values in conformity with the pattern of said voltage pulses.

5. A combination to claim 4 which includes pulse shaping network means connected between the output terminal means of said monostable multivibrator means and said control terminal means of said gate means.

6. A combination according to claim 4 in which said key controlled signal source means comprises at least two signal sources, said gate means comprising a gate connected between the output side of each said signal source and said signal receiver means. said control terminal means comprising a control terminal for said gate, said multivibrator means comprising a multivibrator for each said gate, said output terminal means comprising an output terminal for each said multivibrator connected to the control terminal of the respective gate, said trigger terminal means comprising a trigger terminal for each said multivibrator connected to said source of voltage pulses, and said switch means comprising a switch between each trigger terminal and said source of voltage pulses.

7. A combination according to claim 6 which includes means for supplying respectively different patterns of voltage pulses from said selected patterns thereof to the respective trigger terminals of said multivibrators.

8. A combination according to claim 1 in which said signal source means comprises the solo manual and the accompaniment manual and the pedal clavier of an electronic organ and said signal receiver means comprises the electroacoustic system of the organ, said gate means comprising a first gate connecting the output from. said accompaniment manual to said electroacoustic system and a second gate connecting the output from said pedal clavier to said electroacoustic system, said control terminal means comprising a respective multivibrator for each gate and each having a respective trigger terminal, said switch means comprising a switch connecting each said trigger terminal to said source of biasing voltage, means connecting each trigger terminal to said source of voltage pulses, and each said multivibrator having a respective output terminal connected to the said control terminal of the respective gate.

9,. A combination according to claim 8 which includes means for supplying respectively different rhythmic patterns of pulses from said source of voltage pulses to the respective trigger terminals of said multivibrators.

10. A combination according to claim 9 in which said source of voltage pulses comprises a rhythm unit having voltage pulse generating means, a plurality of terminals to which said voltage pulses are supplied according to selectable predetermined repetitive patterns, and circuit means including terminal isolating diodes connecting selected ones of said plurality of terminals to each said trigger terminal of said multivibrators.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,842,701 DATED October 22, 1974 INVENTOR(S) John W. Robinson and Arthur W. Ross It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, lines 13, 27, 55 and 63, delete "29" and "31" and re alace by 29 and 31' In the drawings:

Switches 29 and 31 should be designated 29' and 31' in Figure 3.

Signed and Scaled this Twentyethird D y of November 1976 sent Arrest:

RUTH c. MASON 'c. MARSHALL DANN Arresting Officer Commissioner nj'lalenl: and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,842,701 DATED October 22, 1974 INVENTOR(S) John W. Robinson and Arthur W. Ross It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown betow:

Column 6, lines 13, 27, 55 and 63, delete "29" and "31" and re alace by 29 and 31' In the drawings Switches 29 and 31 should be designated 29' and 31' in Figure 3.

Signed and Scaled this Twenty-third of November 1976 [SEALl' Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parents and Trademarks 

1. The method of operating an electronic organ having solo and accompaniment manuals and a pedal clavier and an electroacoustic system supplied thereby which comprises; connecting a respective gate having a voltage sensitive control terminal between the output side of each of said accompaniment manual and pedal clavier and said electro-acoustic system, supplying steady state gate opening voltage to the control terminal of each said gate for conventional organ playing and during which organ sounds are produced continuously while corresponding keys of the accompaniment manual and pedal clavier are depressed, and selectively interrupting said steady state opening voltage supply and instead supplying respective trains of pulses of gate opening voltage to the respective control terminals of said gates according to selected predetermined repeated and respective rhythm patterns for playing of the organ with depressing of keys of the accompaniment manual and pedal clavier producing sounds which are intermittent in conformity with the patterns of pulses supplied to the control terminals of the respective gates.
 2. The method according to claim 1 in which the individual pulses of gate opening voltage supplied to the control terminals of the respective gates are of respectively different duration.
 3. The method according to claim 1 in which the individual pulses of gate opening voltage supplied to the control terminal of the gate for the accompaniment manual are of shorter duration than those supplied to the control terminal of the gate for the pedal clavier.
 4. In combination; key controlled signal source means operable to develop electric tone signals, tone signal receiver means including electroacoustic means operable to convert the tone signals to sound, gate means having input terminal means connected to the output side of said signal source means and output terminal means connected to the input side of said signal receiver means, said gate means having control terminal means and varying in impedance in conformity with variations in voltage at said control terminal means, means forming a source of voltage pulses which occur in selectable predetermined repetitive rhythmic patterns, monostable multivibrator means having output terminal means connected to the control terminal means of said gate means, said multivibrator means having trigger terminal means connected to said source of voltage pulses, a source of bias voltage which will hold said multivibrator means in one state when supplied to the said trigger terminal means thereof, said one state of said multivibrator means being that state in which the voltage supplied to said control terminal means makes the impedance of the said gate means low, and switch means connected between said source of bias voltage and said trigger terminal means and in one position connecting said source of bias voltage to said trigger terminal means to hold said multivibrator means in said one state and in another position disconnecting said source of bias voltage from said trigger terminal means thereby releasing said multivibrator means to the control of pulses supplied thereto from said source of voltage pulses for rhythmic changes of state of said multivibrator means, said multivibrator means when under the control of said voltage pulses from said source of voltage pulses causing the impedance of said gate means to alternate between high and low values in conformity with the pattern of said voltage pulses.
 5. A combination to claIm 4 which includes pulse shaping network means connected between the output terminal means of said monostable multivibrator means and said control terminal means of said gate means.
 6. A combination according to claim 4 in which said key controlled signal source means comprises at least two signal sources, said gate means comprising a gate connected between the output side of each said signal source and said signal receiver means, said control terminal means comprising a control terminal for said gate, said multivibrator means comprising a multivibrator for each said gate, said output terminal means comprising an output terminal for each said multivibrator connected to the control terminal of the respective gate, said trigger terminal means comprising a trigger terminal for each said multivibrator connected to said source of voltage pulses, and said switch means comprising a switch between each trigger terminal and said source of voltage pulses.
 7. A combination according to claim 6 which includes means for supplying respectively different patterns of voltage pulses from said selected patterns thereof to the respective trigger terminals of said multivibrators.
 8. A combination according to claim 1 in which said signal source means comprises the solo manual and the accompaniment manual and the pedal clavier of an electronic organ and said signal receiver means comprises the electroacoustic system of the organ, said gate means comprising a first gate connecting the output from said accompaniment manual to said electroacoustic system and a second gate connecting the output from said pedal clavier to said electroacoustic system, said control terminal means comprising a respective multivibrator for each gate and each having a respective trigger terminal, said switch means comprising a switch connecting each said trigger terminal to said source of biasing voltage, means connecting each trigger terminal to said source of voltage pulses, and each said multivibrator having a respective output terminal connected to the said control terminal of the respective gate.
 9. A combination according to claim 8 which includes means for supplying respectively different rhythmic patterns of pulses from said source of voltage pulses to the respective trigger terminals of said multivibrators.
 10. A combination according to claim 9 in which said source of voltage pulses comprises a rhythm unit having voltage pulse generating means, a plurality of terminals to which said voltage pulses are supplied according to selectable predetermined repetitive patterns, and circuit means including terminal isolating diodes connecting selected ones of said plurality of terminals to each said trigger terminal of said multivibrators. 